1. Field of the Invention
The present invention relates to a filter element which is used in a fuel filter for a vehicle to prevent generation of static electricity.
2. Description of Related Art
Since static electricity is generated in a filter element when fuel is filtered by a filter element, various techniques for preventing the static electricity have been proposed.
For example, a filtering material for a fuel filter is disclosed in JP-A 50-38861. The filter sheet is composed of pulp mixed with acryl type fiber which is impregnated with composite resin to form a solid filter element.
Generally, when the fuel filter element formed of filter sheet is held in all insulating resin case, static electricity is generated when fuel is passing through the filter element. Therefore, the above publication proposes a filter member composed of pulp which is charged with minus electricity and acryl type fiber which is charged with plus electricity when fuel passes through the filtering material so that they neutralize the static electricities of minus and plus at the same time, thereby preventing generation of the static electricity even if the filter element is held in an insulating case.
The above conventional filter member is formed by the following steps. That is, fiber of cotton linter pulp mixed with acryl type fiber of 10 weight percentages is formed into a sheet having a specified thickness, permeability and porosity and, thereafter, the sheet is hardened by adding phenol resin. The acryl type fiber in this case is mixed as a composition to be charged with plus electricity for neutralizing the fiber of the cotton linter pulp which is charged with minus electricity when it filtrates fuel.
However, in the conventional filter element described above, it is difficult to provide a filter element which satisfies both the desired filter performance and the desired anti-static effect.